Invertebrates/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby. TIM: I guess Grandpa hasn't used the boat lately. Tim and Moby are inspecting the underside of a small boat. It is covered with starfish and barnacles. The starfish are five-sided stars. The barnacles look like little bumps with holes in the top. The scene changes to a sealed bottle floating in the water with a rolled up piece of paper inside. Moby reaches down and picks it up. Tim reads a letter that was inside the bottle. TIM: Dear Tim and Moby, I need to describe invertebrate animals. Can you help? From, Miles. Well, most of these creatures on the bottom of this boat here belong to the invertebrate group. Tim points to the underside of the boat. TIM: Vertebrates are animals that have a backbone or spinal column. Invertebrates are animals that do not. The screen is divided left-right. The left side shows a low-resolution, outline side-view of a person with the backbone in clearer detail. The right side shows a similar outline only view of a sea anemone, which looks like sac with tentacles on top. MOBY: Beep? TIM: Yeah, that makes us vertebrates. Well, me anyway. Heh. Tim and Moby are standing in front of the water. TIM: About 95 percent of animal species are invertebrates, which are classified into different groups, or phyla. There is a circle graph figure. • Vertebrates 5% • Invertebrates 95% TIM: Sponges, cnidarians, flatworms, roundworms, mollusks, annelids, arthropods, and echinoderms are all examples of invertebrates. As Tim speaks, an example of each animal is shown as he is saying the name of the phylum. • sponge: an animal that looks like a dish-washing sponge. • cnidarians: a jellyfish. • flatworms: a long flat animal with a slight widening at one end that appears to be a head. Two small black dots on the head give the appearance of eyes. • roundworms: a long, skinny tubular shaped animal with no other distinguishing feature shown. • mollusks: an octopus. • annelids: a segmented earthworm. • arthropods: an insect. • echinoderms: a starfish. MOBY: Beep? TIM: Well, that's just the beginning—all the invertebrate phyla are broken down even more. Looking at something called "body symmetry" helps scientists to classify invertebrates. Animals with body parts arranged in a circle around a central point have radial symmetry. The screen splits left-right. On the left is a sand dollar. A small, circular animal with six holes around the circle. Dashed lines highlight the symmetry and demonstrate that the sand dollar could be rotated through one-sixth of a complete circle and look the same. On the right is a starfish. The starfish is shaped like a five-pointed star, and dashed lines indicate the five-fold symmetry. The starfish can be rotated through one-fifth of a complete circle and it will look the same. TIM: Animals with bilateral symmetry have two halves that will match if you draw a line down the center of their bodies. A split screen shows a butterfly on the left and a lobster on the right. Both animals' heads are pointed up. Dashed vertical lines through the center of each animal divide the animals into mirror image halves. TIM: Asymmetric animals have no definite shape at all. A sponge is sitting on the sea floor. TIM: Hey, don't do that! Moby is standing in the water, holding a sponge and squeezing it. TIM: Sponges are among the simplest animals. They filter food out of the water that passes through their bodies. The screen shows Tim talking on the left, and a sponge on the right. The water flow direction is illustrated by dark arrows entering the sponge and light arrows exiting. TIM: Cnidarians sometimes have tentacles around their mouths with stinging cells that shoot out to stun and catch prey. A jellyfish swims across the scene. TIM: Radial symmetry helps cnidarians find food passing by from any direction. Another jellyfish enters view from the bottom of the screen and swims up. TIM: Flatworms have long flat bodies and bilateral symmetry. Most flatworms are parasites that invade other organisms and live off of them. A flatworm is shown in an inset in front of a farm scene. The flatworm is a flat animal with a slight widening at one end that appears to be a head. Two small black dots on the head give the appearance of eyes. The inset shrinks and moves into a water trough, indicating the animal is very small. A pig is drinking from the trough. TIM: Roundworms are the most widespread animal on Earth—billions of them can live in a single acre of soil! Roundworms, such as heartworms, are animal parasites, but roundworms can be plant parasites, or decomposers, or even predators. Two roundworms are shown on a background surrounded by small spheres. The roundworms are long, skinny tube-shaped animals. Tim: Mollusks, like snails and mussels and clams, are soft-bodied invertebrates, often with a protective shell and a muscular foot that allows them to move around and anchor themselves. A snail is moving across the dirt. TIM: Land mollusks have lungs, and water mollusks use gills to breathe. The screen splits up-down and the snail moves up with the upper half. The bottom half of the screen shows a clam sitting on the sea floor while a squid swims by. TIM: Segmented worms like earthworms, leeches, and marine worms, are also known as annelids. Annelids are made up of ringed segments. A segmented earthworm is shown. It has multiple segments of roughly the same length, except near the middle is one larger segment roughly three times longer than the rest. TIM: Arthropods are the largest and most diverse group of animals. As Tim speaks, the screen fills with drawings of a lobster, a tick, a crab, a butterfly, a house fly and a spider. TIM: The word arthropod means jointed foot, so it makes sense that arthropods have jointed parts like claws, legs, and antennae. They have bilateral symmetry and segmented bodies. Echinoderm means spiny skin, and that's definitely one thing you'll find in these animals. A scene of the sea floor shows a starfish in the foreground sitting on a rock. Behind the starfish are two other animals moving slowly along the sea floor. They are round and gray and appear to have small spines sticking out all around their bodies. TIM: They also have an internal skeleton of bone-like plates, a water-filled network of veins, and thousands of tube feet. Echinoderms use their radial symmetry to eat as filter feeders, predators, or bottom feeders. Moby's feet and lower legs are visible as Moby walks through the scene. MOBY: Beep. Moby surfaces from underwater, covered in starfish and barnacles. Tim laughs. TIM: I told you not to stay down there so long. Tim is looking off to the right when a starfish flies into the scene and sticks to his face. He grunts twice and reaches up to pull the starfish off of his face. Category:BrainPOP Transcripts Category:BrainPOP Science Transcripts